JP2684137B2 - Cathode ray tube and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to cathode ray tubes having an interference fit implosion protection band fitted around the faceplate panel, and more particularly to a light emitting screen disposed on the inside surface of the faceplate panel. And a cathode ray tube having an interference fit implosion protection band with means for maintaining alignment of the electron beam in.

[0002]

BACKGROUND OF THE INVENTION U.S. Pat. No. 4,701,802 issued Oct. 20, 1987 describes a cathode ray tube in which an explosion-proof interference fit band is fitted around the panel and the tension exerts a compressive force on the panel. ing. The band, the recess for adjusting to a value suitable for correcting the deformation of the panel caused by evacuating the cathode-ray tube the value of the effective cross-sectional area of the bands is provided. Deformation of the panel causes the electron beam to misalign on the screen surface. The size of the recess is determined based on the amount of misalignment correction theoretically calculated using the data of the deformation of the panel obtained by the measurement. In this way, the deformation of the panel surface is substantially corrected and the electron beam misalignment is minimized.

A drawback of the system shown in the above US patent is that it requires a plurality of ready-made implosion-proof bands with different recess lengths to obtain tension ranges for different panel deformations. Therefore, it is necessary to prepare bands of very different kinds of specifications, and by doing so, it is possible to attach an incorrect band to the cathode ray tube and overcorrect or undercorrect the panel deformation. There is also the possibility of causing it.

[0004]

SUMMARY OF THE INVENTION A cathode ray tube according to the present invention has an evacuated envelope having a faceplate panel with a mold match line. A light emitting screen is provided on the inner surface of the panel.
The envelope includes a funnel portion and a neck portion. The funnel portion is connected to the panel. An electron gun that generates at least one electron beam and projects it toward a screen is arranged in the neck portion. An interference fit implosion protection band is fitted around the panel and the tension of the band is configured to exert a compressive force on the panel. The band contains a portion of double material thickness, a portion of which extends forward of the mold abutment line. The improvement of this band compared to the conventional band is that the value of the effective area of the above double thickness portion is adjusted to a value suitable for giving the deformation compensation to the face plate panel. The result is that the alignment of the electron beam on the screen is maintained.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a color cathode ray tube 10 comprising a rectangular faceplate panel 12, a tubular neck 14 and a rectangular funnel 15 connecting them. The funnel portion 15 is provided with an inner conductive coating (not shown) that contacts the anode button 16 and extends to the neck portion 14. The panel 12 comprises a face plate for observation, that is, a substrate 18 for observation, and a peripheral flange, that is, a side wall portion 20, and the side wall portion 20 is sealed to the funnel portion 15 by a glass frit 21.

The face plate panel 12 is manufactured by a molding method in which glass is put into a two-part mold (not shown). Therefore, the side wall portion 20 has a convex seam 22 as shown in FIG. 3, which is formed at a position where the two parts of the mold abut against each other and is commonly called a mold abutting line. In addition, the side wall portion 20 of the face plate panel 12
Is thicker at a portion connected to the observation face plate 18 than at a portion where the open end is sealed to the funnel portion 15. The sidewalls 20 are angled to improve the molding process and to facilitate the operation of pulling the molded glass panel from the mold. That is, the glass portion located in front of the mold abutment line 22 is tilted at a small angle β with respect to the side wall portion connected to the face plate. A typical value of the angle β is, for example, about 5.5 °. Lead line (break /
Another convex seam 23, called a line, is formed rearwardly from the mold abutment 22. The glass portion behind the drawing line 23 is inclined at an angle γ with respect to the side wall portion connected to the face plate. A typical value of this angle γ is, for example, about 3 ° to 7 °. Due to this deviation from the drawing line 23, the work of drawing the panel from the mold is further facilitated.

A three color phosphor screen 24 is disposed on the inner surface of the face plate 18. The screen 24 shown in FIG. 3 preferably comprises a plurality of screen elements consisting of red, green and blue light emitting phosphor stripes R, G and B, these stripes further comprising three stripes appearing in a periodic sequence. That is, it is a line type screen in which three sets of stripes are arranged so as to form each color group, that is, each pixel, and extend in a direction substantially perpendicular to the plane in which the electron beam is generated. In this example, the phosphor stripe extends vertically when used in a normal viewing mode. Desirably, each phosphor stripe is
As is known, they are separated from each other by a light absorbing matrix material 25. The screen may be a dot type screen instead of the line type screen. A thin conductive layer 26, preferably made of aluminum, is used for the screen 2
4 is a means for supplying a uniform potential to the screen 24 and for reflecting the light emitted from the phosphor element to the observation side via the face plate 18. Screen 24 and aluminum layer 2 provided thereon
6 forms a screen structure.

Returning to FIG. 1, the porous color selection electrode or shadow mask 27 has a plurality of spring members 28 which engage with the respective studs 29 embedded in the side wall portion 20.
Is removably attached to the screen assembly at a predetermined distance by conventional means. The electron gun 30 schematically shown by a dotted line is
Is arranged in the center of the screen, and the three electron beams 31 are projected along the concentrated path so as to hit the screen 24 through the openings of the mask 27. The electron gun 30 may be any known type of cathode ray tube electron gun.

The cathode ray tube 10 is designed for use with an external magnetic deflection yoke, such as the yoke 32 located at the funnel-neck junction. York 32
Generates a magnetic field when energized, and the magnetic field causes the electron beam 31 to scan the screen 24 in the horizontal and vertical directions to draw a rectangular raster. Contact the deflection start surface (zero polarization direction portion
Is shown near the center of the yoke 32 by the line P-P in FIG. For simplicity of illustration, the actual curvature of the deflected beam path in the deflection region is not shown.

An interference fit implosion protection band 34 is shown in FIGS. 2 and 3. As a typical manufacturing method of this band, a steel strip is formed and both ends thereof are connected to form a connecting portion 36. Stretch the band by stretching it in a rectangular loop with rounded corners. The circumferential dimension of the loop at room temperature is slightly smaller than the circumferential dimension of the panel 12. Heating the band 34 to 30 0 ° C.乃 optimum 50 0 ° C. extent, the loop extends to the size that can come on the mold abutting line 22 by sliding the periphery of the side wall portion 20. The band 34 shrinks as the temperature decreases,
Firmly surround the face plate panel 12,
The tension is increased to compress the side wall portion 20. The control of the compressive force on the side wall 20 can be accurately performed by controlling the yield point and the thickness of the band 34. Band 34
As the temperature of the
4, the straight sidewalls 20 join the fusion area of the panel where the straight sidewalls 20 merge with the curved ends of the panel 12, primarily at the corners of the panel sidewalls where the band 34 is in contact. The force is thus transmitted to the corners of the panel and further into the faceplate panel 12. Band 34
Does not move substantially because the corners are in contact with the corners of the panel 12, and the sides of the band 34 first adjust themselves to balance the force of the band. A significant portion of the strain in panel 12 is therefore concentrated in the corner fusion area,
The tension of the band 34 causes a controlled compressive force to be applied to the corners of the band 34 and applied to the corners of the faceplate panel 12 via the bands 34. This inwardly directed compressive force offsets at least part of the outward tension generated at the corners of the face plate due to the atmospheric pressure applied to the face plate when the picture tube is exhausted. When these forces are balanced, the screen 24 will be properly spaced with respect to the shadow mask 27 and each electron beam 31 will be aligned with the corresponding color emitting phosphor screen element to provide the proper color purity.

However, when the inwardly directed compressive force produced by the tension of the band 34 becomes greater than the outwardly directed tension of the faceplate panel 12 produced by atmospheric pressure, the faceplate 18 is shown in FIGS. 3 and 4. As described above, the dome shape is raised up to the new face plate position 18 'by the amount δ proportional to the difference between the above two forces, that is, it is deformed outward. As a result of this dome-shaped ridge, the screen 24 has a new screen position 2.
Move to 4 '. Since this dome-shaped ridge is not necessarily uniform at all locations, the shadow mask 27 cannot provide sufficient compensation. As a result, the electron beam that has passed through the aperture of the shadow mask 27 is not properly aligned with the corresponding phosphor screen element, resulting in a mismatched state. This inconsistent state is shown in FIG. in this way,
When the face plate 18 is raised in the dome shape by the distance δ, the element of the screen 24 moves to the screen position 24 '. Therefore, for example, the electron beam 31 originally intended to be applied to the blue emitting phosphor element of the screen 24 is
While impinging on the blue emitting phosphor element at the screen position 24 ', it also partially hits the adjacent red emitting phosphor element, degrading the color purity.

In this embodiment, the steel strip used for band 34 has an overall width of about 76.2 m that is not folded back.
m (about 3.0 inches), thickness 1.07 to 1.14 m
m (0.042 to 0.045 inch) and a yield strength of 2600 to 3300 Kg / cm ² (3
7,000 to 47,000 psi). FIG.
Further, as shown in FIG. 3, a portion W ₁ of one side edge portion 38 of the strip is folded back to form an overlapping portion, and a portion having a double material thickness is formed on the face plate side of the band. The folded portion W ₁ has a width of about 25.4 mm (about 1.0 inch). Accordingly, band 34 has a workable width W of about 50.8 mm (about 2.0 inches). A plurality of openings 40 formed by incising the band portion adjacent to the return Shi side edge portion 42 other non-folded at those for example lancet-shaped.
Each opening 40 is non-folding return Shi about 9.5mm from the side edge 42
It has bases 44 that are separated by a distance D (about 0.375 inches). By forming a thin strip of band material outside the plane of the band 34, a clip receiving and holding section 4 for engaging and holding a degaussing coil clip (not shown).
6 is provided. Mounting lugs 48 are provided at each corner of the band 34 for fixing the picture tube 10 in a container (not shown).
In the above part, the band 34 is the same as the conventional type.

The problem with the band 34 described above is that the tension of the band changes significantly as the material thickness and yield strength change. The thickness of the band can be controlled within a relatively narrow range (1.07 to 1.14 mm), but the yield strength changes drastically (2600 to 3300 Kg / cm ² ). Band materials to hold are expensive. Only the portion of the band adjacent to the fusion area of the faceplate panel 12 is applied to the faceplate panel to offset the outward force generated in the panel by atmospheric pressure, so that a portion of the band 34 is folded back to the faceplate side of the band. A portion having twice the thickness of the material is formed on the surface. Therefore, the amount W _{1 of the} overlapping portion is 25.4 mm.
(Therefore, the total effective width is 50.8 mm), and the material thickness and the yield strength are the upper limits of 1.14 mm and 3300 Kg, respectively.
/ Cm ² , the tension T ₁ given by the overlapped portion of the folded band 34 is T ₁ = Y ×
A (however, Y is the yield strength of 3300 kg / cm ² , A is the area of 50.8 mm × 1.14 mm = 58 mm ² = 0.
58 cm ² ), ie (1) T ₁ = 3300K
a ^{g / cm 2 × 0.58cm 2 =} 1910Kg.

The yield strength is 2950 Kg / cm ² (4
At 2000 psi, the thickness is 1.10 mm (0.0435
The tension T ₂ obtained by a similar folded superposition band is (2) T ₂ = 2950 Kg / cm ²
X50.8 mm x 1.10 mm = 1650 Kg.

The yield strength and the thickness are respectively set to the upper limits of 330.
It was found that when approaching 0 Kg / cm ² and 1.14 mm, the obtained band tension of 1910 Kg caused the face plate 18 to be excessively deformed, that is, raised in a dome shape to cause electron beam misalignment. .

[0016] In order to maintain the integrity of each electron beam against the respective colors radiating elements of the screen, to correct the interference fit implosion protection bands with high yield strength, as shown in FIG.
The yield strength of the band material is measured for each set of materials.
When the yield strength is close to the upper limit of 3300 Kg / cm ² , the amount W ₁ of the band overlapping portion is reduced by the amount W ₂ to obtain a band having an overlapping portion of W ₃ . The reduction of this superimposition part is, for example,
This is done by deleting the overlapping portion corresponding to the portion W ₂ . A desirable deletion method is to cut off the overlapping portion of the band 34. In the following example, the overlapping portion is W ₁ = 25.4 mm
(1.0 inch) when the reduced _W 3 = to 19.1 mm (0.75 inches) from, and shows how the tension applied to the fusion area of the faceplate panel 12 How You are reduced. In each case, the yield strength of the band material is 330
It is 0 Kg / cm ² and the thickness is 1.14 mm. That is, (1) T ₁ = 3300 Kg / cm ² × 50.8 mm
X1.14mm = 1910Kg, while (3)
T ₃ = 3300 Kg / cm ² × (25.4 mm × 1.1
4 mm + 19.1 mm x 1.14 mm) = 3300 Kg
/ Cm ² × (29.0 mm ² +21.7 mm ² ) = 33
The ^{00Kg / cm 2 × 50.7mm 2 =} 1670Kg.

Thus, the upper limit thickness of 1.14 mm and 3
The tension of 1670 Kg obtained by deleting the folded overlap portion of the band 34 having the upper limit yield strength of 300 Kg / cm ² by 6.3 mm (0.25 inch) is:
With an upper limit thickness of 1.14 mm and an overlap of 25.4 mm, the yield strength is equal to the tension obtained with a band of only 2890 Kg / cm ² . In other words, the band tension directed inward is sufficient for the panel to offset the value of the effective cross-sectional area of the double thickness section against the outward tension created by atmospheric pressure on the evacuated picture tube. Can be controlled by adjusting to a value suitable for obtaining. Therefore, the novel band prevents the domed ridges of the faceplate and maintains the alignment of the electron beam 31 on the screen 24.

In general, the amount of tension applied to the fused area of the faceplate panel is dependent upon the draw line 23 and the non-folded line.
It is not significantly affected by the tension provided by the portion of the band material between the side edges 42.
As shown in FIG. 3, the extraction line 23 is separated from the fusion area, and when the break angle γ is large, the portion of the band 34 behind the extraction line 23 does not contact the side wall portion 20. Even when this break angle γ is at its minimum, the inward tension resulting from this band portion has little effect on the relatively distant fusion zone. Therefore, even with modifications to the non <br/> folding return Shi lateral edge 42 of the band 34, no effect of compensating the domed ridges of the face plate due to a band material having a yield strength of the upper limit value. Therefore, the present invention
It may be used in combination with the invention described in Japanese Patent Application No. 4-117880. In the invention of this Japanese Patent Application No. 4-117880, the tension of the band, by providing a plurality of slots to reduce the cross-sectional area of the band in communication with the opening 40 in the non-folding return Shi lateral edge 42 near the band Keep below the minimum design value of the connecting part. In addition to reducing the tension of such a band, its maximum tensile strength is also reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a cross section along a part of a tube axis of a color cathode ray tube according to the present invention.

FIG. 2 is a front view showing a part of a cathode ray tube and a novel interference fit implosion protection band.

3 is a cross-sectional view of a portion of the faceplate and novel interference fit implosion protection band of the video tube shown in FIG.

4 is an enlarged cross-sectional view of a region inside a circle 4 in FIG.

[Explanation of symbols]

10 cathode ray tube 11 envelope 12 faceplate panel 14 neck portion 15 funnel portion 18 tight face plate 22 molded abutment line 24 luminescent screen 30 the electron gun 31 the electron beam 34 fit implosion protection band W ₁ folded portion W ₃ folded portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-95046 (JP, A)

Claims (2)

(57) [Claims] 1. A face plate panel having a mold abutment line, a light emitting screen disposed on an inner surface of the panel, a funnel portion connected to the panel, and at least one electron beam An evacuated envelope having a neck portion having an electron gun for projecting onto the screen therein, and an interference fit implosion protection band that is fitted around the panel and provides compressive force to the panel as a result of the tension it presents. And the band has a material thickness of 2
Has a fold portion, a portion of the moiety is distracted in front of the abutment line, the width of the thickness Saga double portion, the band
The tension of the panel is equal to the tension of the above panel due to atmospheric pressure.
Ku has been to compensate the deformation of the panel, anionic Kyokusenkan characterized by Rukoto is maintained alignment of the electron beam on the screen by the Re its <br/>. 2. A funnel comprising a faceplate panel having a mold abutment line, a light emitting screen disposed on an inner surface of the panel , a funnel portion and a neck portion.
Parts are connected to the panel, the inside the neck portion generates a small Do <br/> Kutomo one electron beam that Yusuke therein an electron gun for projecting to the screen, is exhaust outer envelope and, clamping Mari fit implosion protection bands formed around the panel
And as a result of the tension in this band
A method of manufacturing a cathode ray tube, comprising: an interference-fitting implosion protection band for providing a contracting force, comprising : a) determining the outward tension of the panel due to atmospheric pressure.
And b) determining the thickness and yield point of the band material, and c) inwardly facing the band at a given material width .
Calculating a tension force, at least one of the having ends that d) opposite
Forming the band from strip material, parts of 2 times the thickness of the material by that form a superimposing section a portion of the bands that are e) above SL formed partially folded back < making a fraction and f) doubling the above by removing an amount of the material
The integrating unit having a thickness amounts reduces, the upper Symbol band
Apply the calculated inward tension to the required outside of the panel.
The method comprising equal tension side facing, g) affixing together the opposing ends of the band at the connecting portion, h) before fitting the band, on the SL band cold dimensions the panel stretched to the small loop-like than the surrounding
A stage to extend the size of the band by the this, the upper Symbol stretched bar down <br/> de as i) the size of the upper Symbol stretched bands is greater than the dimension of the circumference of the panel Heating; j) fitting the heated band around the panel such that at least a portion of the folded back portion is located in front of the mold abutment line. , k) stage in which the upper Symbol fitted the bands is a cold obtain state
When manufacturing method of negative polar tube made.